The Issues of Catchment Boundaries Delimitation in a Suburban Area – the Case Study of Poznań Metropolitan Area, Poland

摘要

The urbanisation and suburbanisation processes are considered to have a detrimental impact on the environment. Increasing the share of the impervious surfaces is one of their main negative effects, particularly in and near the cities, affecting the water relations of basins. It also results in new catchment boundaries formation and, in many cases, changes in the physiographic parameters affecting the accuracy of hydrological and hydraulic calculations of small suburban catchments. This study is an attempt to delimit the catchment boundaries located in the suburban area of Poznań city, Poland, in three variants: according to the Raster Hydrographical Map of Poland and Raster Topographical Map of Poland, digital elevation model, and rainwater sewage system. The analyses were conducted with ArcGIS software, and the results were additionally verified with geodesic measurements on site. This work focuses mainly on the impact of anthropogenic pressure on the catchment shape and the course of its boundaries. The analyses were conducted on the Rów WB stream catchment located in the Skórzewo village, Dopiewo municipality, which stands out within the Poznań Metropolitan Area as the area where the suburbanisation process is the most intensified. This study proved that the agrotechnical and drainage works performed in undeveloped, agricultural areas affected catchment shape and size as much as suburbanisation itself. According to the authors, the suburban catchment boundaries should be regularly updated due to the intensity of the new investments development and additionally verified on site.